1. Field of the Invention
The present invention relates to a display control apparatus to display an image on a display device such as a liquid crystal display panel and a method of controlling the display control device.
2. Description of the Related Art
Conventionally, in a liquid crystal display having an active matrix, occurrence of a line image due to influence of noise of an image signal noise, noise of an output circuit and the like may degrade image quality. Japanese Patent Laid-Open No. 2003-99016 (counterpart U.S. Pat. Nos. 6,943,765 and 7,598,969) proposes correcting an output difference between D/A converter channels with respect to an error by each system which occurs upon generation of phase-expanded image signal by a D/A converter, thereby reducing occurrence of a line image due to the output error.
However, the technique disclosed in Japanese Patent Laid-Open No. 2003-99016 reduces the line image that occurs due to an output error between the D/A converter channels, but does not reduce the influence on an image due to a change in image data.
For example, when 12-bit digital data that is input into the D/A converter changes from (100000000000) to (011111111111), the change in the digital data appears through the ground or wired pattern in an analog signal as an output from the D/A converter. This is called DAC output noise. As a result, the noise is displayed as a display image noise (vertical line noise). Conventionally, reduction of such noise has not been considered.